使用fill自动填充

@TableField(fill = FieldFill.INSERT)
@TableField(fill = FieldFill.DEFAULT)

自动填充类型

package com.example.mybatisplus.handler;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.util.Date;

@Component
public class MyMateObjectHandler implements MetaObjectHandler {

    @Override
    public void insertFill(MetaObject metaObject) {
        this.setFieldValByName("create_time", new Date(), metaObject);
        this.setFieldValByName("update_time", new Date(), metaObject);
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        this.setFieldValByName("update_time", new Date(), metaObject);
    }
}

悲观锁

直接锁死

乐观锁

不锁死

@Version
private Integer version;

解决并发问题

package com.example.mybatisplus.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

//乐观锁
@Configuration
public class MybatisConfig {
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
//        实例化乐观锁
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
//        添加乐观锁插件
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        return interceptor;
    }
}

    @Test
    void test15() {
        QueryWrapper<Users> wrapper = new QueryWrapper<>();
//        wrapper.like("username","1");
        Page<Users> page = new Page<>(1,2); //当前页面,一个页面多少条
        usersMapper.selectPage(page,wrapper);
        List<Users> records = page.getRecords();//查询出来的结果集
        long pages = page.getPages();
        long total = page.getTotal();
        long current = page.getCurrent();
        for (Users user : records) {
            System.out.println(user+",pages:"+pages+",total:"+total+",current:"+current);
        }
        System.out.println(records);
    }

分页查询,以及返回的数据

当前页面等的数据.

mybatis代码生成器

autogenerator 自动代码生成器